Bard College Bard Digital Commons Senior Projects Spring 2017 Bard Undergraduate Senior Projects Spring 2017 Michael Faraday’s “Lines of Force” and the Role of Heuristic Models in Early Electromagnetic Field Theory Nicolas Sandy Engst Matthews Bard College, [email protected] Follow this and additional works at: https://digitalcommons.bard.edu/senproj_s2017 Part of the Epistemology Commons, History of Science, Technology, and Medicine Commons, Intellectual History Commons, and the Philosophy of Science Commons This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License. Recommended Citation Engst Matthews, Nicolas Sandy, "Michael Faraday’s “Lines of Force” and the Role of Heuristic Models in Early Electromagnetic Field Theory" (2017). Senior Projects Spring 2017. 278. https://digitalcommons.bard.edu/senproj_s2017/278 This Open Access work is protected by copyright and/or related rights. It has been provided to you by Bard College's Stevenson Library with permission from the rights-holder(s). You are free to use this work in any way that is permitted by the copyright and related rights. For other uses you need to obtain permission from the rights- holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/or on the work itself. For more information, please contact [email protected]. Michael Faraday’s “Lines of Force” and the Role of Heuristic Models in Early Electromagnetic Field Theory Senior Project submitted to The Division of Social Studies of Bard College By Nicolas S. Engst Matthews Annandale-on-Hudson, New York May 2017 Acknowledgements I want to thank my project advisers, professors Greg Moynahan and Matthew Deady, for their invaluable assistance and encouragement. This project would have been impossible without their help. Furthermore, I thank professor Alice Stroup for her insight and commentary. I am indebted to Dr. Peter Skiff for his instruction and guidance, and for introducing me to the historical study of science. Many of the themes explored herein were prompted from our discussions. Lastly, I wish to express my deep gratitude towards my parents for their enduring love, support, and friendship. Note to the Reader Michael Faraday’s writings were published in a number of different collections and posthumous editions. Unless otherwise noted, citations refer to Faraday’s Experimental Researches in Electricity: Guide to a ​ First Reading edited by Howard J. Fisher. These are simply attributed as “Faraday” followed by a ​ paragraph number. Citations from the unabridged editions are written as “Electricity” and the volume ​ ​ number. All references to Faraday use his in-text paragraph numbers, and quotes containing parenthesized numbers are in-text references to previous paragraphs appearing within the same work. References to Faraday’s Experimental Researches in Chemistry and Physics are written as “Chemistry” followed by the ​ ​ ​ ​ page number. Finally, references to Faraday’s correspondence cite Frank A. J. L. James’ The ​ Correspondence of Michael Faraday. These appear as “Correspondence” followed by the letter number. ​ ​ ​ Table of Contents Introduction 1 The Field Concept 1 Bibliographical Note 6 Section I: Models of Force and Space 9 Faraday’s Philosophical Influences 10 The “Lines of Force” and Their Particles 17 The “Lines of Force” and the Intervening Medium 30 The Gymnotus Analogy 36 Section II: Heuristic Models and Natural Truth 42 Speculation and the Theory as Model 43 Relative Models of Nature 51 Physical Lines of Force 53 Illumination and the Extension of the Senses 58 Epilogue 65 Appendix 71 Bibliography 75 Michael Faraday reading a newspaper. John Watkins, c. 1863 1 Introduction After more than four decades of ground breaking research in chemistry and physics, Michael Faraday, the premiere experimentalist of the Royal Institution, prepared to give one of his many popular lectures. Indeed, Faraday was famous as both an accomplished scientist and a distinguished public speaker. In addition to the usual members of the Institution, the Prince Consort Albert was, on this occasion, in attendance. Seizing this opportunity to present his insights on the methods of intellectual discipline, Faraday articulated his beliefs about the limitations of the perception. He argued that, while reality was made manifest through the senses, they could not themselves provide an adequate understanding of the world. Faraday outlined the difficulty in effectively applying the mind: “Let me next endeavour to point out what appears to me to be a great deficiency in the exercise of the mental powers in every direction; three words will express this great want, deficiency of judgment."1 This ​ ​ judgement was the ability to effectively interpret the disposition and impressions of the senses. For this reason, the mind required the authoritative guide of disciplined reason. Errors in judgement resulted from a “simple and direct result of our perfectly unconscious state."2 Because all perception of the world came from the senses, “the mind has to be instructed with regard to the senses and their intimations through every step of life; and where the instruction is imperfect, it is astonishing how soon and how much their evidence fails us."3Without proper discipline, the 1 Faraday, “Lecture on Mental Education”, Chemistry, p. 465 ​ ​ 2 Ibid. p. 465 3 Ibid. p. 466 2 mind would be unable to adequately perceive the events affecting the senses. Thus leaving the individual unable to distinguish between entities of the environment and the phantasms of their own mind. Though Faraday’s Lecture on Mental Education was given later in his career, in ​ ​ 1855, it reflected a lifelong interest in intellectual development. The proper interpretation and perception of effects were staples of scientific investigations. Experimental demonstrability was a critical component in Faraday’s investigation of natural phenomena. Without making a phenomenon manifest to the senses, it would remain purely an artifact of conjecture. Chief among Faraday’s contributions to science were his experimental researches in electromagnetism. These investigations introduced electromagnetic phenomena as occurring in a medium or field, of force; fundamentally shifting the attention of ​ ​ science to the activity which transpires between objects. Experimental demonstration was not the only prerequisite for a functional understanding of these forces. As Faraday asserted in the lecture discussed above, the mind required an interpretive tool to decipher the results of experiment. This tool was the adoption of scientific theories as a heuristic models.4 Heuristics and analogies played an invaluable role in effectively reshaping Faraday’s conceptualization of electromagnetic forces. They permitted newly delineated phenomena to be visualized beyond traditional categorizations, effectively creating new boundaries appreciable to the senses. Because these new entities were conceptual in origin, they were necessarily artificial, limited to the detectable attributes ascribed to them. By conceiving of theory as a tool of heuristic modeling, the investigator became aware of each theory’s limitations and relative 4 That is, an illustrative model emphasizing utility over truthfulness. Though the model is not an accurate depiction of system, it is, in some way, a depiction which facilitates understanding by highlighting useful albeit theoretical qualities in the subject. 3 utility. Though two theories may be irreconcilable, they each may illuminate unique qualities of phenomenon. Thus one could appeal to the whole range of different interpretations, making use of their specific qualities and implications. This understanding delineated a divide between the conceptual reality of theories which are intellectually perceived and events in physical reality which are experientially sensed. Faraday was thus able to explore representations of natural phenomena as they became available to his senses. Through the separation of the conceptual model from natural truth, the investigator became free to consciously explore the relationship between abstract and tangible forces. By becoming aware of the relativity of theories, Faraday became able to consciously expand his perception of the natural world. Many historians have debated the origins and influential extent of this guiding belief so as to better understand the success and structure of Faraday’s ideas.5 His work in electromagnetism distanced electricity from the study of chemistry, and laid the ground for the more modern field theories of Maxwell and Einstein. The debate surrounding Faraday’s own conception of a field theory has raised two major questions: When did he conceive of the field? And how did he conceive of field?6 Though Faraday himself never presented his investigations as a field theory, his portrayal of electromagnetic phenomenon has nevertheless warranted its consideration as the predecessor of modern theories.7 5 For an overview of different interpretations of Faraday’s epistemology, see Nersessian, “Faraday’s Field Concept”, in Faraday Rediscovered, 1985. ​ ​ 6 See Nersessian, 1985. 7 Faraday does refer to ‘fields’ in his later writings, though the term is used alongside the more prevalent term “medium." 4 The historian Nancy Nersessian has argued that, when examining the formations of concepts - such as fields - a concise understanding of the concept itself should be explicitly given. Due to the evolving definition of field theory